xe2x80x9cStand-upxe2x80x9d plastic pouches or bottles for holding liquids and other pourable products are becoming more popular, in part because of the desire to minimize solid waste, in part because of cost, and in part for other reasons. An early stand-up pouch design (U.S. Pat. No. 3,380,646) was devised by the Doyen Brothers in France. That pouch design, including many variants, is still in use today. It is, in fact, the dominant style. The basic Doyen design consists of two flat sheets seamed together along their sides, with a xe2x80x9cWxe2x80x9d fold running along the bottom. When the pouch is filled, the xe2x80x9cWxe2x80x9d opens and provides a base on which the pouch can stand. The original Doyen design showed the top being sealed straight across, but subsequent modifications include fitments to allow the pouch to be reclosed after opening.
One difficulty in adding a fitment to a Doyen pouch (and to many other pouch designs as well) is that, according to prior art fitment sealing methods, the fitment must be of the xe2x80x9ccanoexe2x80x9d style to create a joint that can be reliably sealed. The canoe type of fitment is an attempt to minimize the change in direction of pouch material as it comes into contact with the fitment, and in so doing, improve the integrity of the joint where the two sides of the pouch come together at the fitment. However, even the use of a canoe shaped fitment does not completely solve the difficulties in sealing a fitment into a pouch, and a more reliable sealing means is desirable. The present invention provides such a means.
A xe2x80x9ccanoexe2x80x9d style fitment is characterized by having a sealing surface that includes relatively sharp changes in direction around the sealing periphery so as to permit the pieces of material being sealed to the fitment to approach the fitment sealing surface (laterally) at relatively shallow angles. Or, put another way, as two webs separate to go around the fitment in opposite directions, the angle of divergence is relatively small. Canoe style fitments are illustrated in, e.g., U.S. Pat. Nos. 5,660,477, 4,415,085, and 4,732,299.
There are at least two other shortcomings of Doyen style pouches with fitments, as compared with the present invention. One is that, because the Doyen body tapers from the bottom to the top, and the present invention has a body that approximates a rectangular parallelepiped, for a given volume contained, the bottle of the present invention requires substantially less material to fabricate. Since material cost is a large part of the cost of flexible packaging, this is a significant factor. Another shortcoming of the Doyen style (and other ungusseted styles), compared to the present invention is that, because the upper body is fabricated from two flat sheets, when the pouch is partly full, the weight of the fitment tends to cause the top of the pouch to fold over, rather than stand erect.
Gusseted bottles (but without fitment) have been made in the past (see U.S. Pat. No. 6,193,416, Kawamata et al., U.S. Pat. No. 6,126,315, Ichikawa et al., and U.S. Pat. No. 5,918,984, LaFleur et al.) Obviously, without a fitment, these prior art containers do not have the utility of the present invention.
U.S. Pat. No. 5,660,477, Ichikawa, discloses a gusseted pouch with a fitment. The fitment shown has flanges protruding from the central section; these create even more sealing problems than a conventional canoe style fitment. Additionally, because of the way the top of the pouch is configured, i.e., the gussets are closed at the top, the fitment weight tends to cause this pouch to fold over when partly full, in a manner very much like a Doyen pouch with fitment.
The invented bottle which could, but preferably does not, utilize canoe style fitments is fabricated from flexible films (i.e., thin plastic, foil, paper, or the like) fed as webs from rolls of material. The bottle includes a gusseted body section that opens so as to form a substantially square or rectangular cross section. The gussets are terminated at the bottom of the bottle to form a substantially flat base, providing stability when the bottle is partially or wholly filled. The top portion of the bottle includes a fitment passing through a necked down portion of the bottle. The fitment is preferably sealed to the neck in two or more sealing operations carried out at different radial angles, preferably, but not necessarily, 90xc2x0, thus assuring an adequate seal between the fitment and the bottle neck around the entire periphery of the fitment.
For purposes of clarity, as pictured herein the fitment is illustrated without a closure. It will be appreciated that threaded, snap, and/or other types of closures are contemplated even though none is shown in the figures.
As opposed to requiring the use of canoe style fitments, as mentioned in the Background section of this Specification, the present invention permits, and preferably utilizes, xe2x80x9ccylindrical basexe2x80x9d fitments. The sealing surface (or xe2x80x9cbasexe2x80x9d) of a cylindrical base style fitment (as that term is used in the present application) is preferably (but not necessarily) substantially parallel to the axis of the fitment, as in the canoe style, but does not include external corners at sharply acute angles around its circumference, as do canoe style fitments. Rather, the circumference is preferably comprised of smooth and preferably convex curves. Having the circumference comprised of smooth curves is intended to facilitate the sealing of web material to the base of the fitment with two overlapping sealing steps applied from different directions. The cross sectional shape of the sealing area of a cylindrical base fitment is preferably circular, but may be oval, or have some other curved shape. While the word xe2x80x9ccylindricalxe2x80x9d is used herein to help define a xe2x80x9cnon-canoexe2x80x9d style of fitment, it should be understood that the fitment may be tapered somewhat (axially) to facilitate insertion or for other reasons.
Alternatively, instead of the sealing surface area of a cylindrical base fitment being comprised of smooth curves, the sealing surface of a cylindrical base fitment (as that term is used in this specification) may include intersections at an angle, provided that the angle is not so acute as to make a second sealing step difficult or impractical. Intersection angles that are greater than about 90xc2x0 are generally deemed to be satisfactory, hence the term xe2x80x9ccylindrical basexe2x80x9d, as used in this specification, refers to the base (i.e., the sealing surface) of a fitment wherein the webs of material surrounding and sealed to the fitment diverge at angles greater than about 90xc2x0 as they separate to encircle the fitment. FIG. 15, which is a fragmentary sectional view of a cylindrical base fitment, illustrates the approximate
minimum angle of approach of surfaces of what is termed here as a xe2x80x9ccylindrical basexe2x80x9d fitment. The base of a cylindrical base style of fitment could, for example, have a hexagonal shape (in cross section).
The preferred method of fabricating the invented bottle generally comprises:
1. feeding two or more webs of material in face to face contact into a fabricating machine, the webs including a pair of gussets,
2. creating perimeter seals for the bottle around a part of the circumference, including the neck portion of the bottle, and shaping the bottle by cutting away areas at the edges of the webs,
3. separating at least one of the incoming webs from the remainder of the webs upstream of the neck portion and inserting a fitment into the neck portion of the bottle, the insertion motion being through what eventually will become the bottom of the bottle,
4. forming the remainder of the perimeter seals of the bottle,
5. severing the bottle from the web,
6. clamping the bottle material to the fitment with a heated clamping means to create a seal between the bottle material and the fitment,
7. Clamping the bottle material to the fitment with a heated clamp a second time, the second clamping being at a different radial angle.